Method for providing notifications for multi-media broadcast/multicast service

ABSTRACT

A method for a multi-media broadcast/multicast service by a base station includes receiving, from a radio network controller (RNC), a command for updating an MBMS notification indicator, the command including notification indicator information and a connection frame number, determining whether a modification period is included in the command, and transmitting a notification indicator starting at a time based on the connection frame number for the modification period if the modification period is included in the command, wherein the notification indicator information is used to generate the notification indicator.

PRIORITY

This application is a Continuation Application of U.S. application Ser.No. 11/658,951, which was filed in the U.S. Patent and Trademark Officeon Jun. 15, 2009, which is a National Phase Entry of PCT InternationalApplication No. PCT/KR2005/002482, which was filed on Jul. 29, 2005, andclaims priority to Chinese Patent Application No. 200410071138.7, whichwas filed on Jul. 29, 2004, the contents of each of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to Wideband Code Division Multiple Accessof the 3G communication system, especially to a method for providingnotifications for a Multi-media Broadcast/Multicast service.

2. Description of the Related Art

The Multimedia Broadcast/Multicast Service (hereinafter referred to asMBMS) is a new service under standardization by 3G Mobile CommunicationSystem Partnership Project (hereinafter referred to as 3GPP). Theservice provided in virtue of broadcast or multicast is anunidirectional point-to-multipoint (i.e. multimedia data sent from asingle data source are transferred to multiple users through networktransmission) service. The most remarkable feature of the service isthat it can make use of radio resources and network resourcesefficiently. MBMS service is mainly used in wireless communicationnetwork system, e.g. Wideband Code-Division Multiple Access system,Global System of Mobile Communication, etc. MBMS service data transferbasically includes following several steps, i.e. data sourcetransmission, middle network transmission, destination cell on-the-airtransmission and user receiving. As shown in FIG. 1, Broadcast andMulticast Service Center 70 (hereinafter referred to as BM-SC) is thedata source for MBMS data transmission; Gateway GPRS Supporting Node 60(hereinafter referred to as GGSN) is used to connect GRPS network withexternal network, such as INTERNET; In MBMS service, the Gateway GPRSSupporting Node connects to the BM-SC and sends MBMS data to specificService GPRS Supporting Node 50 (hereinafter referred to as SGSN); SGSNis used to perform access control on UE as well as mobility management,and sends MBMS data from GGSN to specific Radio Network Controller 30(hereinafter referred to as RNC) at the same time; RNC is used tocontrol a group of base stations like station 23 and 24 and sendsmultimedia data to specific base stations like station 23 and 24; a basestation 23 establishes air common channel 11 for MBMS service of cell 21under the control of the RNC; a base station 24 establishes air commonchannel 12 for MBMS service of cell 22 under the control of the RNC;Terminal User Equipment 10 (hereinafter referred to as UE) is a terminalequipment for MBMS data reception.

FIG. 4 shows a whole process from service announcement, joining of auser, service notification, establishment of radio bearer to leaving ofthe user finally in MBMS service.

401 Subscription: Establish a connection between a user and a serviceprovider, and authorize the user to receive a relevant MBMS service.

402 Service Announcement: Notify a user of services that will beprovided. For example, the system will rebroadcast a football match inBeijing at 7:00 p.m.

403 Joining: Refers to that the user joins a group, i.e. the userinforms the network that he or she is willing to receive this multicastservice.

404 MBMS Session Start: Refers to establish a network resource for MBMSdata transfer.

405 MBMS Notification: Notify the user of MBMS data transfer that willbe performed right away.

406 Data transmission: Refers to the process of transferring MBMSservice data to the user.

407 MBMS Session Stop: Refers to release the network resource after theMBMS service data transfer process is completed.

408 leaving: Oppositely to 403 joining, which indicates that the user isleaving the group, i.e. the user doesn't want to receive the data of acertain service any more.

Because step 405 is the content that the present invention shouldemphasize, it will be introduced in detail in the following. FIG. 2 isreferred for more information. There are many conditions to activate theRNC to perform MBMS notifications, for instance, to inform the UE thatthe MBMS session starts, to re-count the number of users, to inform theUE that the session is completed, etc. Two steps are applied to carryout the MBMS notification: first, an indication bit is set for eachcorresponding MBMS service which needs to send notifications in a cell'sMulti-media Broadcast/Multicast Indication Channel (hereinafter referredto as MICH) (202), and the UE receives the MICH via the air interface(203); next, the corresponding RRC messages are transferred through theMulti-media Broadcast/Multicast Control Channel (hereinafter referred toas MCCH), indicating the actions of the UE (204). The structure of theMICH is shown in FIG. 5. In the MICH, 300 bits are available in use, andin general, only the fore 288 bits are used, leaving alone the rest 12bits. The actual number of MICH bits used in the service is not involvedin the present invention. Here, let N be the number of available bits inan MICH frame, these N bits are divided into Np groups with each groupindicating only one MBMS service group within a frame, and the number ofbits needed for a group is just N/Np.

A time when the UE tunes in the MICH corresponds to its own user ID, andthe tuning in locations each time it wakes up are different to everyframe. In the MBMS, in order to carry out the MBMS notification for allUEs that have subscribed this service, all UEs should be enabled todetect that the notification indication bit NI of the MICH has been setto true for the subscribed service, thus repeating to send said servicenotification within a certain period, which is defined as themodification period, as shown in FIG. 3.

Since the MICH has limitation in information transfer, it exists suchmoment that different services map to the same location of the MICH. Toreduce this probability, a method for spreading NI is proposed in theWCDMA system so that each service's corresponding location NI in a frameis made different from any others with a certain algorithm. In this way,the probability that several services correspond to the same location NIcan be reduced so as to avoid that the notification NI received by theUE is not the very one for the service that the UE has subscribed.

According to this method, the data sent to the Node 13 in each frame isneeded to be calculated by the RNC and transferred to the Node B throughFP. Usually, if indicator of a certain service is true, then thespecific N/Np bits in the MICH must be set as true within the wholemodification period. This means that the RNC should send data to theNode B in every frame, thus, the traffic through an interface Iubbecomes comparatively larger and higher requirements are put forward tothe needed transmission equipments. If this condition could be improved,not only the traffic through the interface Iub can be reduced, but alsothe operating efficiency of the Node B can be enhanced. By the existingtechnique, the contents to be transferred through the MICH are wellcalculated by the RNC according to some algorithm based on mappingrelationship, and generally, the RNC transfers the Np bits to the Node Bthrough the frame protocol FP in the interface lub, with each bitindicating whether the corresponding service is true or false. Then, theNode B maps each bit to the N/Np bits of the MICH and transmits it tothe UE via the air interface.

SUMMARY OF THE INVENTION

The present invention has been made to address the above-mentionedproblems and disadvantages, and to provide at least the advantagesdescribed below. Accordingly, an aspect of the present invention is toprovide a method for providing notifications for multi-mediabroadcast/multicast.

According to an aspect of the present invention, a method for amulti-media broadcast/multicast service by a base station includesreceiving, from a radio network controller (RNC), a command for updatingan MBMS notification indicator, the command including notificationindicator information and a connection frame number, determining whethera modification period is included in the command, and transmitting anotification indicator starting at a time based on the connection framenumber for the modification period if the modification period isincluded in the command, wherein the notification indicator informationis used to generate the notification indicator.

According to another aspect of the present invention, an apparatus foran MBMS by a base station includes a receiver for receiving, from anRNC, a command for updating an MBMS notification indicator, the commandincluding notification indicator information and a connection framenumber, a controller for determining whether a modification period isincluded in the command, and a transmitter for transmitting anotification indicator starting at a time based on the connection framenumber for the modification period if the modification period isincluded in the command, wherein the notification indicator informationis used to generate the notification indicator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a logic device diagram of MBMS;

FIG. 2 is a flowchart of a MBMS notification;

FIG. 3 shows a transmission period of MICH;

FIG. 4 is a flowchart of MBMS multicast service;

FIG. 5 shows a structure of MICH;

FIG. 6 shows a flowchart according to the present invention;

FIG. 7 shows an embodiment of the present invention;

FIG. 8 illustrates the first aspect of the embodiment of the presentinvention;

FIG. 9 illustrates the second aspect of the embodiment of the presentinvention; and

FIG. 10 illustrates the third aspect of the embodiment of the presentinvention.

FIG. 11 illustrates the behavior of Node B of the present invention.

FIG. 12 illustrates the behavior of RNC of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 6 shows the basic content of the present invention. When the RNCneeds to provide MBMS service in some cells, it should establish andconfigure the MICH channel in the cells, and establish and configure thecommon channel for service transmission, which is illustrated in 600.When the RNC needs to carry out the MBMS notification for a certain MBMSservice or several MBMS services (601), it sends the information such asparameters like service ID relative to these services to the Node B(602). With the information received from the RNC, the Node B calculatesthe location NI of each service in a certain frame, then generates anintegrated MICH (603) and transfers it to the UE (604).

In order to calculate the location NI of a certain service group in acertain frame, the Node B needs such information as the service ID, Np,modification period, start time, terminative time, transmission powerand so on.

The first embodiment of the present invention is illustrated in FIG. 7.

When the RNC decides to provide MBMS service to some cells, it needs toestablish the MICH and the common channel for service transmission inthese cells (700). There is only one MICH in each cell, but severalcommon channels can be established in one cell for MBMS servicetransmission according to the different types of services. Some commonchannels can only support one kind of service, but some ones can supportmany kinds of services. The RNC sets the modification period and thestart time at the time it configures the MICH. The modification periodmeans that the content of the information transmitted through the MICHor the content of the control information transmitted through MCCH isjust the same within the period for some MBMS service. For the MICH, theNI corresponding to the service must be set as true in all frames withinone modification period. The start time indicates the time when themodification period starts. In general, the common channel is denoted bythe cell's system frame number SFN which repeats from 0 to 4095. Thevalue of start time ranges from 0 to (modification period−1). Thealgorithm for calculating a new start time for MICH is that the starttime+(modification period)×N, wherein, N denotes the total number ofmodifications within a cycle period of SFN.

When the MBMS service starts or it is needed to carry out the MBMSnotification (701), the RNC informs the Node B of the service ID and thestart time of the MBMS service that needs to be notified (702). In thiscase, if the RNC needs to carry out the MBMS notifications for severalservices simultaneously, it can send the service IDs corresponding tothe several services to the Node B at the same time. The start timeindicates to the time when the Node B should transmit the MICH, and itcan be denoted by an absolute value of SFN, an index of the modificationperiod (i.e., N mentioned above), or a Connection Frame Number. If thestart time is not presented in step 700 by the RNC, it can be presentedhere. Then, the Node B sets the NI locations in each frame for eachservice with the modification period, the start time and the service ID(703), and combines them in one MICH frame. Next, the Node B transmitsthe MICH to the UE through the air interface (704). If neither themodification period nor the start time is presented in step 700 by theRNC, the RNC may inform the Node B of the service ID, the start time andterminative time of the MBMS service that needs to be notified in 702.Both the start time and the terminative time can be denoted by SFN,indicating the start frame number and terminative frame number of thenotified MBMS respectively.

Following three methods can be adopted by the RNC to send the relevantMBMS information to the Node B in 702: by means of a NBAP signaling of acontrol plane, a frame protocol FP of a user plane or the control frameof the user plane.

The first aspect of this embodiment is illustrated in FIG. 8.

The RNC sends the MBMS notification request message to the Node Bthrough the NBAP signaling, which contains a MBMS service list, thestart time and an initial time, or contains the MBMS service list, thestart time and the terminative time. The detailed explanations of thesefour parameters are shown in 702.

The second aspect of this embodiment is illustrated in FIG. 9.

The RNC sends the MBMS service notification request message to the NodeB through the FP of the user plane, which contains the MBMS servicelist, the start time and the initial time, or contains the MBMS servicelist, the start time and the terminative time. The detailed explanationsof these four parameters are shown in 702. The FP should be transmittedthrough the transmission channel of MICH and includes either theinformation of several services or only one service ID. In the lattercase, if it is necessary to send the MBMS notification for severalservices simultaneously, one FP is needed to be transmitted for eachservice.

The third aspect of this embodiment is illustrated in FIG. 10.

The RNC sends the MICH notification indication message to the Node Bthrough the control frame of the user plane, which contains the MBMSservice list, the start time and the initial time, or contains the MBMSservice list, the start time and the terminative time. The detailedexplanations of these four parameters are shown in 702. This controlframe should be transmitted through the common channel that is used totransmit relevant services. If the common channel transmits only oneservice, the control frame includes only one MBMS service ID, otherwise,it possibly includes several MBMS service IDs. Of course, one controlframe can be transmitted for each service, thus the control framecomprises only one MBMS service ID.

The behaviour of the Node B is illustrated in FIG. 11.

1101 Node B receives the command from the RNC to send MBMS Notification.This command can be via NBAP control signaling, or messages via FP inuser plane, or control frame via user plane. This command comprises theMBMS service identifier to notify, start time (SFN or CFN), modificationperiod. Service identifier could be any information related to aspecific MBMS service. The modification period denotes the number offrames to repeat MBMS notification on MICH. 1102 Node B calculates thelocation of NI in every specific frame and the notification frames andthen transmit NI over MICH.

The behaviour of the RNC is illustrated in FIG. 12.

1201 RNC establishes MICH in a cell by sending NBAP message to the NodeB. 1202 RNC sends command to Node B to transmit the MBMS notification inthe cell. This command can be via NBAP control signaling, or messagesvia FP in user plane, or control frame in user plane. This commandcomprises the MBMS service identifier to notify, start time (SFN orCFN), modification period. Service identifier could be any informationrelated to a specific MBMS service. The modification period denotes thenumber of frames to repeat MBMS notification on MICH.

What is claimed is:
 1. A method by a base station, the method comprising: receiving, from a radio network controller (RNC), a command including notification indicator information and a connection frame number; identifying that a modification period is included in the command; and transmitting a notification indicator on a multi-media broadcast/multicast service (MBMS) notification indication channel starting at a MBMS notification indicator channel connection frame number equal to the connection frame number, wherein the notification indicator information is used to generate the notification indicator.
 2. The method of claim 1, wherein the notification indicator is transmitted on the MBMS notification indication channel for a duration equal to the modification period.
 3. The method of claim 1, wherein the command further comprises a common channel identifier.
 4. A base station, comprising: a transceiver; and a controller configured to: receive, via the transceiver from a radio network controller (RNC), a command including notification indicator information and a connection frame number, identify that a modification period is included in the command, and transmit, via the transceiver, a notification indicator on a multi-media broadcast/multicast service (MBMS) notification indication channel starting at a MBMS notification indicator channel connection frame number equal to the connection frame number, wherein the notification indicator information is used to generate the notification indicator.
 5. The base station of claim 4, wherein the notification indicator is transmitted on the MBMS notification indication channel for a duration equal to the modification period.
 6. The base station of claim 4, wherein the command further comprises a common channel identifier. 